Translation:If you want to arrive, do not take this train.
Indonesian, like spanish, japanese, and many other languages, often omit personal pronouns and subjects.
Oftentimes the subject is infered/implied depending on context.
If you listen to Indonesians have a casual conversation together, you'll find that they dont say kamu/kalian/kau or saya/aku/ku as much as we learn in this course.
This depends on which region you speak in. In Western Java, Indonesia, a car is referred to as "mobil".
"Kereta" is usually a shortened form of "kereta api".
If you're in Malaysia, then yes, "Kereta" is "car" in bahasa melayu as far as I know of their spoken usage. I'm not too sure about other regions in Indonesia, but I suspect the Sumatran provinces and Riau Islands, being closer to the Malaysian Peninsula, probably use "Kereta" the same way as you mentioned.